My problem is with x-Axis Mirror
Bone names could be an issue. X-Axis Mirror part (https://docs.blender.org/manual/en/2.80/animation/armatures/bones/editing/bones.html)
Try renaming them to Bone.R and Bone.L

When you have pairs of bones of the same name with just a different “side suffix” (e.g. “.R”/”.L”, or “_right”/”_left” …), once this option is enabled, each time you transform (move/rotate/scale…) a bone, its “other side” counterpart will be transformed accordingly, through a symmetry along the armature local X axis.